The present application claims priority to Japanese Application No. P10-340719 filed Nov. 30, 1998 which application is incorporated herein by reference to the extent permitted by law.
1. Field of the Invention
The present invention relates to a non-aqueous electrolyte battery having a structure that a battery element is accommodated in a casing constituted by a laminate film. More particularly, the present invention relates to improvement in impact resistance of the non-aqueous electrolyte battery.
2. Description of the Related Art
In recent years, a multiplicity of portable electronic apparatuses including camcorders, portable telephones and portable computers have come on the market. An attempt has been made to reduce the size and weight of the foregoing electronic apparatuses. As the portable power sources for the foregoing electronic apparatuses, batteries, in particular, secondary batteries, and more particularly, nonaqueous-electrolyte secondary batteries (so-called xe2x80x9clithium ion batteriesxe2x80x9d) have energetically be researched and developed to reduce the thickness of the battery and realize a foldable structure.
As the electrolyte for the shape-variable battery, solidified electrolytic solution has energetically been studied. In particular, attention is being given to a polymer solid electrolyte into which lithium salt is dissolved in a gel electrolyte, which is a solid electrolyte containing a plasticizer, or a polymer.
On the other hand, the merits of the foregoing battery, which are small thickness and light weight, are attempted to be used. Therefore, a variety of batteries have been studied which have an encapsulating structure which uses a plastic film or a laminate film constituted by bonding a plastic film and a metal sheet to each other.
The conventional battery incorporating the sealed casing made of metal exhibits a merit that the casing has great rigidity. Therefore, the casing of the battery is not easily deformed. Thus, the electrode elements in the battery can satisfactorily be protected from damage. On the other hand, the so-called laminate film suffers from unsatisfactory rigidity. As a result, resistance against external impact is unsatisfactory. Therefore, if the battery is dropped, the electrode element in the battery is susceptible to damage. Thus, there arises a problem in that short circuit easily occurs between the positive electrode and the negative electrode.
In view of the foregoing, an object of the present invention is to provide a nonaqueous electrolyte battery which is capable of satisfactorily protecting an electrode element therein against external impact and which is enclosed in a laminate film.
To achieve the above-mentioned object, there is provided a non-aqueous electrolyte battery comprising: a casing constituted by a laminate film; and a battery element accommodated in the casing and enclosed by welding, wherein a resin layer is formed on one or more surfaces of the battery element so that the battery element and the casing are isolated from each other.
The non-aqueous electrolyte battery having the above-mentioned structure is able to protect the battery element from external impact owing to the impact buffering function of the resin layer. Therefore, if impact is exerted on the battery in a case of dropping or the like, satisfactory reliability can be realized.
Other objects, features and advantages of the invention will be evident from the following detailed description of the preferred embodiments described in conjunction with the attached drawings.